Such a pocket belt conveyor is known from DE 38 37 115 A1, DE-PS 966 618, and DE 66 03 142 U. In the case of the pocket belt conveyors, so-called inside conveyors, known from the first two publications the bulk material is supplied and discharged at the inside of the revolving traction member. The latter comprises supporting belts which are spaced apart and to which transverse members are fixed by retainer means. Inwardly open pockets formed by an endless band are arranged between the supporting belts. The edges of the pockets each are connected firmly to a sidewall which is made of stiff material, whereby the sidewalls act as backing elements of the pocket giving it its shape. The pocket belt conveyor according to DE 38 37 115 A1 has its adjacent transverse members interconnected at their ends by fishplates in such a way that the transverse members and the fishplates together form an articulated sidebar chain connected parallel to the supporting belts and revolving together with them. This arrangement of the pockets with respect to the traction member and the provision of an additional sidebar chain results in a complex and expensive structure of the pocket belt conveyor, as reflected by the greater susceptibility to repair and higher manufacturing cost. Furthermore, sidewalls of stiff material are needed to keep the bottom wall of the pockets in an inclined position with respect to the traction member. The pocket belt conveyor according to DE 66 03 142 U, on the other hand, has no sidewalls at all but instead only flexible pockets which are fastened to transverse members in the form of rods. This known pocket belt conveyor, above all, has the disadvantage that its simple structure, especially the simple way of fastening the transverse members at the supporting belts, makes it unsuitable for use with heavy goods. Experience made with pocket belt conveyors and the more sophisticated requirements to be met in terms of uninterrupted service life have led to new approaches in the design and fastening of pockets in pocket belt conveyors so as to obtain a conveyor belt which, on the whole, is more reliable and suitable for an extreme range of applications.
DE 38 35 619 C2 discloses a normal conveyor belt with a plurality of studded feet which are fixed by their studs on the basic belt so as to extend transversely of the conveying direction and entrain the goods to be conveyed in conveying direction. A mesh fabric is suspended between adjacent studs so as to extend from the tip of one stud to the root of the preceding stud in the direction of conveyance. A fastening rail serves to secure the fabric to the root of the stud and, by this rail, each mesh fabric is fastened indirectly, through the root of the stud, to the basic belt. With this known conveyor belt it is the studs that carry the mesh fabric provided between them and fixed to them. The pockets of a pocket belt conveyor, on the other hand, are suspended directly from the supporting belts and that requires high standards to be met, especially as regards the pockets themselves and their fastening to the supporting belts. Also, the direct fixing of the pockets at the supporting belts means that the pockets are subjected to greater stress than the mesh fabrics which are suspended between the studs of the known conveyor belt when the supporting belts revolve around the drive pulleys or the deviator and deflection pulleys.
DE-AS 12 63 591 discloses a bucket conveyor whose "fastening element" forms part of the pocket (in that case called "bucket") which is made up of a rigid rear portion and a flexible front portion. The only thing comparable to the transverse member of the instant pocket belt conveyor is a transverse bar, the design of which, however, differs from that of the transverse member.
DE 18 29 977 U relates to a pocket belt conveyor with which the recipient bottom is made of a non-flexible material, namely sheet steel, and the planar portion tapering so as to form a pivot pin is made of sheet steel and extends at an angle to the travelling plane of the pivot pins.
DE 38 02 078 describes a pocket belt conveyor comprising upper and lower sprockets and an endless chain moving around them. Pockets are fixed to the chain by means of support frames. Each pocket is formed so as to have sidewalls of reinforced rubber as well as a wall interconnecting the sidewalls and made of transversely stiff cloth. The combination of reinforced sidewalls and transversely stiff cloth provides a pocket of relatively stable configuration which is inclined with respect to the traction member, the pockets being lined up uninterruptedly. The upper, rear edge of the bottom wall of one pocket is bent at the level of the transverse members so as to extend over the lower, front edge of the adjacent pocket. Here the contiguous edges of the adjacent pockets are glued or screwed together.
Finally, the traction member of the pocket belt conveyor known from DE 1 080 480 comprises transverse webs which are reinforced by inserts. Each one of the pockets which are positioned so as to be mutually spaced on the traction member is secured between two adjacent transverse webs. To this end the flexible bottom wall of the pockets is extended all the way to the region of the transverse webs and secured to them. The pockets are defined laterally by sidewalls the shape of which is stiff. The pockets are in an oblique position, as determined by the stiff sidewalls, with respect to the revolving endless traction member.
The problem underlying the instant invention was to improve a pocket belt conveyor of the kind known from DE 66 03 142 U so that it would be distinguished by greater efficiency.